Current computer systems exist for the display and manipulation of data in a spreadsheet-like format. These systems generally display various column headings and row identifiers, with the intersection of the rows and columns containing values.
In the presently existing systems, data in the spreadsheet can be summarized. For example, the data for an entire column could be summed and the sum would be displayed as a total in a summary level. When various quantities are changed in a column, the summary level can be automatically updated to reflect these changes. In existing systems however, a change made to a summary level cannot be prorated back through the data items which make up that summary level.
Many spreadsheet systems and database systems have graphics capabilities. These capabilities allow the representation of the data in graphical form. Some of these systems allow real-time update of graphs as data is changed. Present systems however, do not allow the underlying data to be changed by modifying the graph.